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From: Eric Dumazet <dada1@cosmosbay•com>
To: Stephen Hemminger <shemminger@vyatta•com>
Cc: Paul Mackerras <paulus@samba•org>,
	paulmck@linux•vnet.ibm.com, Evgeniy Polyakov <zbr@ioremap•net>,
	David Miller <davem@davemloft•net>,
	kaber@trash•net, torvalds@linux-foundation•org,
	jeff.chua.linux@gmail•com, mingo@elte•hu, laijs@cn•fujitsu.com,
	jengelh@medozas•de, r000n@r000n•net,
	linux-kernel@vger•kernel.org, netfilter-devel@vger•kernel.org,
	netdev@vger•kernel.org, benh@kernel•crashing.org,
	mathieu.desnoyers@polymtl•ca
Subject: Re: [PATCH] netfilter: use per-cpu recursive lock (v11)
Date: Tue, 21 Apr 2009 06:59:29 +0200	[thread overview]
Message-ID: <49ED52B1.7050601@cosmosbay.com> (raw)
In-Reply-To: <20090420160121.268a8226@nehalam>

Stephen Hemminger a écrit :
> This version of x_tables (ip/ip6/arp) locking uses a per-cpu
> recursive lock that can be nested. It is sort of like existing kernel_lock,
> rwlock_t and even old 2.4 brlock.
> 
> "Reader" is ip/arp/ip6 tables rule processing which runs per-cpu.
> It needs to ensure that the rules are not being changed while packet
> is being processed.
> 
> "Writer" is used in two cases: first is replacing rules in which case
> all packets in flight have to be processed before rules are swapped,
> then counters are read from the old (stale) info. Second case is where
> counters need to be read on the fly, in this case all CPU's are blocked
> from further rule processing until values are aggregated.
> 
> The idea for this came from an earlier version done by Eric Dumazet.
> Locking is done per-cpu, the fast path locks on the current cpu
> and updates counters.  This reduces the contention of a
> single reader lock (in 2.6.29) without the delay of synchronize_net()
> (in 2.6.30-rc2). 
> 
> The mutex that was added for 2.6.30 in xt_table is unnecessary since
> there already is a mutex for xt[af].mutex that is held.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta•com

I reviewed this patch believe its in quite good shape, thanks Stephen.

Then I tested it on a x86_32 8 cpus machine and got no obvious problem.

Signed-off-by: Eric Dumazet <dada1@cosmosbay•com>

Hopefully, next rcu_bh (or whatever name is used) will permit us
to switch back to pure RCU in 2.6.31
 
oprofile snapshot of a tbench session, with light iptables rules.
(4 rules in INPUT chain, 3 rules on OUTPUT)

xt_info_rdlock_bh() uses 0.6786 % of cpu
xt_info_rdunlock_bh() uses 0.1743 % of cpu


CPU: Core 2, speed 3000.77 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000
samples  cum. samples  %        cum. %     symbol name
1248350  1248350       11.3285  11.3285    copy_from_user
534049   1782399        4.8464  16.1749    copy_to_user
480898   2263297        4.3641  20.5390    __schedule
325581   2588878        2.9546  23.4936    ipt_do_table
312697   2901575        2.8377  26.3312    tcp_ack
309381   3210956        2.8076  29.1388    tcp_sendmsg
248238   3459194        2.2527  31.3915    tcp_v4_rcv
230405   3689599        2.0909  33.4824    tcp_transmit_skb
220638   3910237        2.0022  35.4847    ip_queue_xmit
217099   4127336        1.9701  37.4548    tcp_recvmsg
175885   4303221        1.5961  39.0509    tcp_rcv_established
173112   4476333        1.5710  40.6219    __switch_to
165138   4641471        1.4986  42.1205    sysenter_past_esp
149367   4790838        1.3555  43.4759    dst_release
138619   4929457        1.2579  44.7339    sched_clock_cpu
132724   5062181        1.2044  45.9383    lock_sock_nested
121353   5183534        1.1013  47.0396    nf_iterate
119205   5302739        1.0818  48.1214    netif_receive_skb
118859   5421598        1.0786  49.2000    release_sock
112597   5534195        1.0218  50.2218    __inet_lookup_established
112195   5646390        1.0181  51.2399    sys_socketcall
110018   5756408        0.9984  52.2383    tcp_write_xmit
106466   5862874        0.9662  53.2045    __alloc_skb
93386    5956260        0.8475  54.0519    dev_queue_xmit
89229    6045489        0.8097  54.8617    tcp_event_data_recv
85972    6131461        0.7802  55.6418    local_bh_enable
82882    6214343        0.7521  56.3940    skb_release_data
80898    6295241        0.7341  57.1281    ip_rcv
76380    6371621        0.6931  57.8213    skb_copy_datagram_iovec
74782    6446403        0.6786  58.4999    xt_info_rdlock_bh
73593    6519996        0.6678  59.1677    mod_timer
72884    6592880        0.6614  59.8291    sock_recvmsg
71789    6664669        0.6515  60.4806    __copy_skb_header
70560    6735229        0.6403  61.1209    fget_light
68756    6803985        0.6239  61.7449    get_page_from_freelist
68378    6872363        0.6205  62.3654    put_page
68042    6940405        0.6175  62.9829    ip_finish_output
67618    7008023        0.6136  63.5965    page_address
64894    7072917        0.5889  64.1854    tcp_cleanup_rbuf


> 
> ---
> CHANGES 
>   - optimize for UP
>   - disable bottom half in info_rdlock
>   - prevent preempt count overflow
>   - turn off lockdep in writer to avoid bogus warning
>   - optimize unlock_bh
> 
>

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  parent reply	other threads:[~2009-04-21  4:59 UTC|newest]

Thread overview: 215+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.64.0904101656190.2093@boston.corp.fedex.com>
     [not found] ` <20090410095246.4fdccb56@s6510>
2009-04-11  1:25   ` iptables very slow after commit784544739a25c30637397ace5489eeb6e15d7d49 David Miller
2009-04-11  1:39     ` iptables very slow after commit 784544739a25c30637397ace5489eeb6e15d7d49 Linus Torvalds
2009-04-11  4:15       ` Paul E. McKenney
2009-04-11  5:14         ` Jan Engelhardt
2009-04-11  5:42           ` Paul E. McKenney
2009-04-11  6:00           ` David Miller
2009-04-11 18:12             ` Kyle Moffett
2009-04-11 18:32               ` Arkadiusz Miskiewicz
2009-04-12  0:54               ` david
2009-04-12  5:05                 ` Kyle Moffett
2009-04-12 12:30                 ` Harald Welte
2009-04-12 16:38             ` Jan Engelhardt
2009-04-11 15:07           ` Stephen Hemminger
2009-04-11 16:05             ` Jeff Chua
2009-04-11 17:51           ` Linus Torvalds
2009-04-11  7:08         ` Ingo Molnar
2009-04-11 15:05           ` Stephen Hemminger
2009-04-11 17:48           ` Paul E. McKenney
2009-04-12 10:54             ` Ingo Molnar
2009-04-12 11:34             ` Paul Mackerras
2009-04-12 17:31               ` Paul E. McKenney
2009-04-13  1:13                 ` David Miller
2009-04-13  4:04                   ` Paul E. McKenney
2009-04-13 16:53                     ` [PATCH] netfilter: use per-cpu spinlock rather than RCU Stephen Hemminger
2009-04-13 17:40                       ` Eric Dumazet
2009-04-13 18:11                         ` Stephen Hemminger
2009-04-13 19:06                       ` Martin Josefsson
2009-04-13 19:17                         ` Linus Torvalds
2009-04-13 22:24                       ` Andrew Morton
2009-04-13 23:20                         ` Stephen Hemminger
2009-04-13 23:26                           ` Andrew Morton
2009-04-13 23:37                             ` Linus Torvalds
2009-04-13 23:52                               ` Ingo Molnar
2009-04-14 12:27                       ` Patrick McHardy
2009-04-14 14:23                         ` Eric Dumazet
2009-04-14 14:45                           ` Stephen Hemminger
2009-04-14 15:49                             ` Eric Dumazet
2009-04-14 16:51                               ` Jeff Chua
2009-04-14 18:17                                 ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v2) Stephen Hemminger
2009-04-14 19:28                                   ` Eric Dumazet
2009-04-14 21:11                                     ` Stephen Hemminger
2009-04-14 21:13                                     ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3) Stephen Hemminger
2009-04-14 21:40                                       ` Eric Dumazet
2009-04-15 10:59                                         ` Patrick McHardy
2009-04-15 16:31                                           ` Stephen Hemminger
2009-04-15 20:55                                           ` Stephen Hemminger
2009-04-15 21:07                                             ` Eric Dumazet
2009-04-15 21:55                                               ` Jan Engelhardt
2009-04-16 12:12                                                 ` Patrick McHardy
2009-04-16 12:24                                                   ` Jan Engelhardt
2009-04-16 12:31                                                     ` Patrick McHardy
2009-04-15 21:57                                               ` [PATCH] netfilter: use per-cpu rwlock rather than RCU (v4) Stephen Hemminger
2009-04-15 23:48                                               ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3) David Miller
2009-04-16  0:01                                                 ` Stephen Hemminger
2009-04-16  0:05                                                   ` David Miller
2009-04-16 12:28                                                     ` Patrick McHardy
2009-04-16  0:10                                                   ` Linus Torvalds
2009-04-16  0:45                                                     ` [PATCH] netfilter: use per-cpu spinlock and RCU (v5) Stephen Hemminger
2009-04-16  5:01                                                       ` Eric Dumazet
2009-04-16 13:53                                                         ` Patrick McHardy
2009-04-16 14:47                                                           ` Paul E. McKenney
2009-04-16 16:10                                                             ` [PATCH] netfilter: use per-cpu recursive spinlock (v6) Eric Dumazet
2009-04-16 16:20                                                               ` Eric Dumazet
2009-04-16 16:37                                                               ` Linus Torvalds
2009-04-16 16:59                                                                 ` Patrick McHardy
2009-04-16 17:58                                                               ` Paul E. McKenney
2009-04-16 18:41                                                                 ` Eric Dumazet
2009-04-16 20:49                                                                   ` [PATCH[] netfilter: use per-cpu reader-writer lock (v0.7) Stephen Hemminger
2009-04-16 21:02                                                                     ` Linus Torvalds
2009-04-16 23:04                                                                       ` Ingo Molnar
2009-04-17  0:13                                                                   ` [PATCH] netfilter: use per-cpu recursive spinlock (v6) Paul E. McKenney
2009-04-16 13:11                                                     ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3) Patrick McHardy
2009-04-16 22:33                                                       ` David Miller
2009-04-16 23:49                                                         ` Paul E. McKenney
2009-04-16 23:52                                                           ` [PATCH] netfilter: per-cpu spin-lock with recursion (v0.8) Stephen Hemminger
2009-04-17  0:15                                                             ` Jeff Chua
2009-04-17  5:55                                                             ` Peter Zijlstra
2009-04-17  6:03                                                             ` Eric Dumazet
2009-04-17  6:14                                                               ` Eric Dumazet
2009-04-17 17:08                                                                 ` Peter Zijlstra
2009-04-17 11:17                                                               ` Patrick McHardy
2009-04-17  1:28                                                           ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3) Paul E. McKenney
2009-04-17  2:19                                                             ` Mathieu Desnoyers
2009-04-17  5:05                                                               ` Paul E. McKenney
2009-04-17  5:44                                                                 ` Mathieu Desnoyers
2009-04-17 14:51                                                                   ` Paul E. McKenney
2009-04-17  4:50                                                             ` Stephen Hemminger
2009-04-17  5:08                                                               ` Paul E. McKenney
2009-04-17  5:16                                                               ` Eric Dumazet
2009-04-17  5:40                                                                 ` Paul E. McKenney
2009-04-17  8:07                                                                   ` David Miller
2009-04-17 15:00                                                                     ` Paul E. McKenney
2009-04-17 17:22                                                                     ` Peter Zijlstra
2009-04-17 17:32                                                                       ` Linus Torvalds
2009-04-17  6:12                                                             ` Peter Zijlstra
2009-04-17 16:33                                                               ` Paul E. McKenney
2009-04-17 16:51                                                                 ` Peter Zijlstra
2009-04-17 21:29                                                                   ` Paul E. McKenney
2009-04-18  9:40                                                             ` Evgeniy Polyakov
2009-04-18 14:14                                                               ` Paul E. McKenney
2009-04-20 17:34                                                                 ` [PATCH] netfilter: use per-cpu recursive lock (v10) Stephen Hemminger
2009-04-20 18:21                                                                   ` Paul E. McKenney
2009-04-20 18:25                                                                   ` Eric Dumazet
2009-04-20 20:32                                                                     ` Stephen Hemminger
2009-04-20 20:42                                                                     ` Stephen Hemminger
2009-04-20 21:05                                                                       ` Paul E. McKenney
2009-04-20 21:23                                                                     ` Paul Mackerras
2009-04-20 21:58                                                                       ` Paul E. McKenney
2009-04-20 22:41                                                                         ` Paul Mackerras
2009-04-20 23:01                                                                           ` [PATCH] netfilter: use per-cpu recursive lock (v11) Stephen Hemminger
2009-04-21  3:41                                                                             ` Lai Jiangshan
2009-04-21  3:56                                                                               ` Eric Dumazet
2009-04-21  4:15                                                                                 ` Stephen Hemminger
2009-04-21  5:22                                                                                 ` Lai Jiangshan
2009-04-21  5:45                                                                                   ` Stephen Hemminger
2009-04-21  6:52                                                                                     ` Lai Jiangshan
2009-04-21  8:16                                                                                       ` Evgeniy Polyakov
2009-04-21  8:42                                                                                         ` Lai Jiangshan
2009-04-21  8:49                                                                                           ` David Miller
2009-04-21  8:55                                                                                         ` Eric Dumazet
2009-04-21  9:22                                                                                           ` Evgeniy Polyakov
2009-04-21  9:34                                                                                           ` Lai Jiangshan
2009-04-21  5:34                                                                                 ` Lai Jiangshan
2009-04-21  4:59                                                                             ` Eric Dumazet [this message]
2009-04-21 16:37                                                                               ` Paul E. McKenney
2009-04-21  5:46                                                                             ` Lai Jiangshan
2009-04-21 16:13                                                                             ` Linus Torvalds
2009-04-21 16:43                                                                               ` Stephen Hemminger
2009-04-21 16:50                                                                                 ` Linus Torvalds
2009-04-21 18:02                                                                               ` Ingo Molnar
2009-04-21 18:15                                                                               ` Stephen Hemminger
2009-04-21 19:10                                                                                 ` Ingo Molnar
2009-04-21 19:46                                                                                   ` Eric Dumazet
2009-04-22  7:35                                                                                     ` Ingo Molnar
2009-04-22  8:53                                                                                       ` Eric Dumazet
2009-04-22 10:13                                                                                         ` Jarek Poplawski
2009-04-22 11:26                                                                                           ` Ingo Molnar
2009-04-22 11:39                                                                                             ` Jarek Poplawski
2009-04-22 11:18                                                                                         ` Ingo Molnar
2009-04-22 15:19                                                                                         ` Linus Torvalds
2009-04-22 16:57                                                                                           ` Eric Dumazet
2009-04-22 17:18                                                                                             ` Linus Torvalds
2009-04-22 20:46                                                                                               ` Jarek Poplawski
2009-04-22 17:48                                                                                         ` Ingo Molnar
2009-04-21 21:04                                                                                   ` Stephen Hemminger
2009-04-22  8:00                                                                                     ` Ingo Molnar
2009-04-21 19:39                                                                                 ` Ingo Molnar
2009-04-21 21:39                                                                                   ` [PATCH] netfilter: use per-cpu recursive lock (v13) Stephen Hemminger
2009-04-22  4:17                                                                                     ` Paul E. McKenney
2009-04-22 14:57                                                                                     ` Eric Dumazet
2009-04-22 15:32                                                                                     ` Linus Torvalds
2009-04-24  4:09                                                                                       ` [PATCH] netfilter: use per-CPU recursive lock {XIV} Stephen Hemminger
2009-04-24  4:58                                                                                         ` Eric Dumazet
2009-04-24 15:33                                                                                           ` Patrick McHardy
2009-04-24 16:18                                                                                           ` Stephen Hemminger
2009-04-24 20:43                                                                                             ` Jarek Poplawski
2009-04-25 20:30                                                                                               ` [PATCH] netfilter: iptables no lockdep is needed Stephen Hemminger
2009-04-26  8:18                                                                                                 ` Jarek Poplawski
2009-04-26 18:24                                                                                                 ` [PATCH] netfilter: use per-CPU recursive lock {XV} Eric Dumazet
2009-04-26 18:56                                                                                                   ` Mathieu Desnoyers
2009-04-26 21:57                                                                                                     ` Stephen Hemminger
2009-04-26 22:32                                                                                                       ` Mathieu Desnoyers
2009-04-27 17:44                                                                                                       ` Peter Zijlstra
2009-04-27 18:30                                                                                                         ` [PATCH] netfilter: use per-CPU r**ursive " Stephen Hemminger
2009-04-27 18:54                                                                                                           ` Ingo Molnar
2009-04-27 19:06                                                                                                             ` Stephen Hemminger
2009-04-27 19:46                                                                                                               ` Linus Torvalds
2009-04-27 19:48                                                                                                                 ` Linus Torvalds
2009-04-27 20:36                                                                                                                 ` Evgeniy Polyakov
2009-04-27 20:58                                                                                                                   ` Linus Torvalds
2009-04-27 21:40                                                                                                                     ` Stephen Hemminger
2009-04-27 22:24                                                                                                                       ` Linus Torvalds
2009-04-27 23:01                                                                                                                         ` Linus Torvalds
2009-04-27 23:03                                                                                                                           ` Linus Torvalds
2009-04-28  6:58                                                                                                                             ` Eric Dumazet
2009-04-28 11:53                                                                                                                               ` David Miller
2009-04-28 12:40                                                                                                                                 ` Ingo Molnar
2009-04-28 13:43                                                                                                                                   ` David Miller
2009-04-28 13:52                                                                                                                                     ` Mathieu Desnoyers
2009-04-28 14:37                                                                                                                                       ` David Miller
2009-04-28 14:49                                                                                                                                         ` Mathieu Desnoyers
2009-04-28 15:00                                                                                                                                           ` David Miller
2009-04-28 16:24                                                                                                                                             ` [PATCH] netfilter: revised locking for x_tables Stephen Hemminger
2009-04-28 16:50                                                                                                                                               ` Linus Torvalds
2009-04-28 16:55                                                                                                                                                 ` Linus Torvalds
2009-04-29  5:37                                                                                                                                                   ` David Miller
     [not found]                                                                                                                                                     ` <20090428.223708.168741998.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2009-04-30  3:26                                                                                                                                                       ` Jeff Chua
     [not found]                                                                                                                                                         ` <b6a2187b0904292026k7d6107a7vcdc761d4149f40aa-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-04-30  3:31                                                                                                                                                           ` David Miller
2009-05-01  8:38                                                                                                                                                     ` [PATCH] netfilter: use likely() in xt_info_rdlock_bh() Eric Dumazet
2009-05-01 16:10                                                                                                                                                       ` David Miller
2009-04-28 15:42                                                                                                                                     ` [PATCH] netfilter: use per-CPU r**ursive lock {XV} Paul E. McKenney
2009-04-28 17:35                                                                                                                                       ` Christoph Lameter
2009-04-28 15:09                                                                                                                               ` Linus Torvalds
2009-04-27 23:32                                                                                                                           ` Linus Torvalds
2009-04-28  7:41                                                                                                                             ` Peter Zijlstra
2009-04-28 14:22                                                                                                                               ` Paul E. McKenney
2009-04-28  7:42                                                                                                                 ` Jan Engelhardt
2009-04-26 19:31                                                                                                   ` [PATCH] netfilter: use per-CPU recursive " Mathieu Desnoyers
2009-04-26 20:55                                                                                                     ` Eric Dumazet
2009-04-26 21:39                                                                                                       ` Mathieu Desnoyers
2009-04-21 18:34                                                                               ` [PATCH] netfilter: use per-cpu recursive lock (v11) Paul E. McKenney
2009-04-21 20:14                                                                                 ` Linus Torvalds
2009-04-20 23:44                                                                           ` [PATCH] netfilter: use per-cpu recursive lock (v10) Paul E. McKenney
2009-04-16  0:02                                                 ` [PATCH] netfilter: use per-cpu spinlock rather than RCU (v3) Linus Torvalds
2009-04-16  6:26                                                 ` Eric Dumazet
2009-04-16 14:33                                                   ` Paul E. McKenney
2009-04-15  3:23                                       ` David Miller
2009-04-14 17:19                               ` [PATCH] netfilter: use per-cpu spinlock rather than RCU Stephen Hemminger
2009-04-11 15:50         ` iptables very slow after commit 784544739a25c30637397ace5489eeb6e15d7d49 Stephen Hemminger
2009-04-11 17:43           ` Paul E. McKenney
2009-04-11 18:57         ` Linus Torvalds
2009-04-12  0:34           ` Paul E. McKenney
2009-04-12  7:23             ` Evgeniy Polyakov
2009-04-12 16:06             ` Stephen Hemminger
2009-04-12 17:30               ` Paul E. McKenney

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